The major objective of this work is to isolate, purify and determine the structure of the antitumor alkaloids present in Catharanthus roseus and Ghazya stricta. The Madagascan plant Catharanthus roseus has been well studied, and several active antitumor principles have been isolated. However, a number of fractions containing alkaloids and exhibiting very high activity in vivo remain to be studied. The crude alkaloid mixtures will be separated initially by pH gradient techniques and subsequently by column chromatography, combined as appropriate and then evaluated biologically either in vivo or in vitro depending upon the activity of the original fraction. Work on the Indian plant Rhazya stricta is at a much earlier stage, but it is expected that activity will be found in the alkaloid fraction. In any event, biologically monitored fractionation will be used to isolate the active constituents. Isolated compounds will be identified by their mp, mass, UV and IR spectra, optical rotation and PMR and CMR spectra. Structure elucidation will be carried out by interpretation of these data, chemical correlation with known compounds and in particularly difficult cases by single crystal X-ray crystallography.